Memory devices are typically provided as internal, semiconductor, integrated circuits in computers or other electronic systems. There are many different types of memory including volatile and non-volatile memory. Volatile memory can require power to maintain its data (e.g., host data, error data, etc.) and includes random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), synchronous dynamic random access memory (SDRAM), and thyristor random access memory (TRAM), among others. Non-volatile memory can provide persistent data by retaining stored data when not powered and can include NAND flash memory, NOR flash memory, and resistance variable memory such as phase change random access memory (PCRAIVI), resistive random access memory (RRAM), and magnetoresistive random access memory (MRAM), such as spin torque transfer random access memory (STT RAM), among others.
Electronic systems often include a number of processing resources (e.g., one or more processors), which may retrieve and execute instructions and store the results of the executed instructions to a suitable location. A processor can comprise a number of functional units such as arithmetic logic unit (ALU) circuitry, floating point unit (FPU) circuitry, and a combinatorial logic block, for example, which can be used to execute instructions by performing an operation (e.g., a compute operation) on data (e.g., one or more operands). As used herein, a compute operation can be, for example, a Boolean operation, such as AND, OR, NOT, NOT, NAND, NOR, and XOR, and/or other operations (e.g., invert, shift, arithmetic, statistics, among many other possible operations) that may involve manipulating data. For example, functional unit circuitry may be used to perform the arithmetic operations, such as addition, subtraction, multiplication, and division on operands, via a number of logical operations. A compute operation such as described above can be distinguished from a “memory operation,” which, as used herein, can refer to an operation that does not involve data manipulation (e.g., via a functional unit often associated with a processing resource). Examples of memory operations include data read, data write, and data refresh operations.
A number of components in an electronic system may be involved in providing instructions to the functional unit circuitry for execution. The instructions may be executed, for instance, by a processing resource such as a controller and/or host processor. Data (e.g., the operands on which the instructions will be executed) may be stored in a memory array that is accessible by the functional unit circuitry. The instructions and data may be retrieved from the memory array and sequenced and buffered before the functional unit circuitry begins to execute instructions on the data. Furthermore, as different types of operations may be performed in one or multiple clock cycles through the functional unit circuitry, intermediate results of the instructions and data may also be sequenced and buffered.
In many instances, the processing resources (e.g., processor and associated functional unit circuitry) may be external to the memory array, and data is accessed via a bus between the processing resources and the memory array to execute a set of instructions. Processing performance may be improved in a processing in memory device, in which a processor may be implemented internally and/or near to a memory (e.g., directly on a same chip as the memory array). A processing in memory device may save time and/or may reduce power consumption by reducing or eliminating the amount of data transfer over a bus in association with performing compute operations, for example.
In various instances, it can be useful for a host, such as a host processor, to access status information from a memory device. For example, such status information may relate to flow control, debugging, exceptions, and/or errors, among various other status information associated with operations performed by the memory device.